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The first sign of a budding whitefly infestation might be a host of tiny white flying insects rising from a plant when its leaves are disturbed. If left untreated, whiteflies (Trialeurodes vaporariorum) can quickly overtake a plant, penetrating the stems and sucking out the lifegiving juices within.
What are whiteflies?
Whiteflies are related to mealybugs and aphids, but not household flies, and are identified by their yellow-hued bodies and two sets of white wings. Studies show there are at least 115 species of whiteflies that feed on both houseplants and outdoor plants, and they propagate rapidly during the warm summer season.
“High temperatures alongside high humidity levels create optimal conditions for whitefly population booms,” says Shawn Gleason, an entomologist and founder of Bugs Encyclopedia.
Getting rid of them requires vigilance and persistence, but it’s doable. Best of all, you won’t need to resort to harmful pesticides.
Research shows that whiteflies have a life cycle of six distinct stages: the egg; the first, second, third, and fourth larval stages (sometimes referred to as the immature stages); and the adult stage.
Bemisia tabaci, a common type of whitefly, lays eggs on both sides of plant leaves, with 82 degrees Fahrenheit being the optimal temperature for growth. The eggs are small and white, hatching in just 5 to 9 days. Adults emerge after about 16 to 31 days.
Whiteflies have over 150 natural predators such as ladybird beetles, predaceous bugs, lacewings, phytoseid mites, and spiders, which can help keep their populations in check. By introducing these predators into affected areas or creating habitats that attract them, you can effectively control whitefly infestations without the need for chemical pesticides.
“Beneficial insects play a crucial role in controlling whiteflies organically,” Gleason explains. “Noteworthy predators include Encarsia formosa (a parasitic wasp) and various species of lady beetles that feed voraciously on whitefly larvae.”
MATERIALS AND TOOLS
A few common ingredients and some simple tools can be used for eradicating whiteflies. You probably won’t need all of these items to get rid of the insects, but you’ll need at least a few to keep whiteflies from setting up residence in your garden.
Handheld vacuum
Garden nippers or pruning shears
Spray bottle
Liquid dish soap
Earthworm castings
Neem oil
Companion plants, such as marigolds, chives, and dill
Before You Begin
At the first indication that whiteflies are settling on plants, some growers reach for toxic chemicals to control them. Though this strategy might work, research shows that whiteflies have developed resistance to some pesticides.
The following steps to eradicating these tiny destroyers involve some manual labor, and mixing up an inexpensive, natural DIY repellent. Controlling whiteflies via chemical-free means is better for the environment, and the right choice for treating food-producing plants.
4 Steps to Eradicating Whiteflies in the Garden
Step 1: Vacuum infected plants.
The first step in stopping whiteflies is to get them off the plant. Shooing them away or flicking them off won’t work. They’ll come right back. Instead, suck the insects up with a small handheld vacuum.
Vacuuming will remove the flies and their larvae—just be sure to lift the leaves and vacuum the undersides as well. Vacuuming can also be helpful in controlling other types of indoor pests.
Once you’ve hoovered the little pests, don’t dump the collection bin in the trash. The whiteflies will fly out and head back to the plants again. A better idea is to dump the little buggers into a plastic bag, and seal the bag before throwing it away.
Step 2: Remove the most damaged leaves from the plant.
Whiteflies tend to feed on one leaf and then another, sucking out all the leaf’s juices before moving on to the next one. When this happens, the plant continues to send energy to the damaged leaves until they’re removed, though the damaged leaves are well past saving.
- Using a sharp garden nipper or pruning shears, clip off wilted leaves as well as those that are covered in a sticky, waxy fluid. The fluid, called honeydew, is secreted by the whiteflies after ingesting the plant’s vital juices.
- Seal the clipped-off leaves in a plastic bag before tossing them in the trash.
Step 3: Clean leaves and stems with a DIY whitefly spray.
A simple solution made from liquid dish soap and water will kill adult whiteflies without harming plants.
- Add 1 tablespoon of liquid dish soap to 1 gallon of water and mix well.
- Pour the solution into a plastic spray bottle and spray it on all infested plants, saturating the leaves’ upper and undersides and the stems.
The dish soap solution will kill adult whiteflies. If eggs remain on the plants, they will hatch in 3 to 4 days and reinfest them.
Be sure to respray affected plants every couple of days to kill any whiteflies that have hatched in the meantime.
Step 4: Bolster plant and soil health.
Keeping plants healthy by watering and fertilizing will make them strong enough to survive a whitefly infestation.
A weak plant will succumb more quickly than a healthy one. If you find that whiteflies are a persistent problem in the garden or on your indoor plants, consider adding earthworm castings to your soil.
Earthworm castings repel whiteflies and, as castings decompose, they become organic fertilizer to boost the plant’s health. Castings can also be sprinkled on leaves to keep whiteflies away.
How to Prevent Whiteflies in the Garden
Keeping a close eye on your garden will allow you to get rid of whiteflies before they can damage or kill your plants. Additionally, “regular monitoring of plants for early signs of infestation coupled with maintaining plant health through proper nutrition helps deter whiteflies,” Gleason says. “Reflective mulches can also disorient these pests, reducing their likelihood of settling on your plants.”
Neem oil, an extract of the seeds of neem trees, can get rid of whiteflies without harming plants. This natural pesticide repels whiteflies and can be applied to plants at the first sight of a white-winged pest.
Neem oil comes in various forms, including concentrated liquid that can be diluted in water and sprayed on plants. It is also available as a granular that can be mixed into the soil, or a dust that can be applied to leaves and stems. Follow the package directions for use.
Think about long-term protection.
It’s not always easy to spot a whitefly infestation and stop the bugs before they substantially damage plants, which is why taking steps to repel the insects is just as important, if not more so, as treating existing infestations. Companion planting can help.
Plants that naturally repel whiteflies include catnip, bee balm, basil, chives, dill, and marigolds.
By planting these natural repellents in the garden, whiteflies, and other pests such as spider mites are less likely to move in.
FAQs
Q: How do I kill whiteflies?
To effectively kill whiteflies, consider using liquid dish soap or neem oil, or introducing natural predators such as ladybird beetles.
Q: Can vinegar get rid of whiteflies?
While vinegar has been shown to repel certain insects, it’s not a guaranteed method for getting rid of whiteflies. Consider using alternative methods such as neem oil or liquid dish soap.
Q: What is the cause of whitefly infestation?
Infestations can be caused by a variety of factors such as hot temperatures, the presence of host plants, or excessive nitrogen fertilization.
Q: Do whiteflies live in soil?
Whiteflies primarily occur on plant leaves instead of soil.
Q: Do whiteflies bite?
Whiteflies do not bite humans. They often feed on sap from plant stems and leaves.
Final Thoughts
Without quick action, whiteflies can severely damage or destroy many types of plants, including squash, cucumber, tomatoes, and other warm-season vegetables. They can also damage roses and other ornamentals.
Citrus trees are not immune to whiteflies, either. The good news is that these methods for stopping a whitefly infestation and preventing future ones will not harm plants or the environment.